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From: guy@sun.uucp (Guy Harris)
Newsgroups: net.unix-wizards
Subject: Re: TTY Inquiry
Message-ID: <2888@sun.uucp>
Date: Sat, 12-Oct-85 20:02:22 EDT
Article-I.D.: sun.2888
Posted: Sat Oct 12 20:02:22 1985
Date-Received: Tue, 15-Oct-85 07:18:51 EDT
References: <482@scirtp.UUCP>
Distribution: net
Organization: Sun Microsystems, Inc.
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> Currently under Bell UNIX, data communications for ttys are
> uni-directional.  For example, once a port is conditioned to send out
> data, it can not readily receive data.

What?  When I log into a UNIX system, I can type at it at the same time it's
typing at me.  What do you mean by "conditioned to send out data"?  You
can't have one process blocked on a "read" on that port and doing a "write"
on the port at the same time on any current UNIX.  Programs like "cu"
usually work by having two processes, one doing the reads and one doing the
writes.

	Guy Harris